Louis was hit by Allen in the third quarter of Sunday's game following a Vikings' interception. As Minnesota defensive back Antoine Winfield returned the interception, Louis was blindsided by Allen on a block, and his knee twisted as he fell to the ground. Louis was forced to leave the game and did not return.
Right tackle Gabe Carimi filled in for Louis at right guard. Louis will have an MRI Monday.
Speaking after the game, Allen made it clear that he did not intend to injure Louis, and he believes the hit was clean.
"I thought it was a legal hit," he said. "He's running to make a tackle, so I just wanted to block him. I never intentionally try to hurt anybody. I turned around, he was running to make a tackle and I threw myself into him to make a block. My condolences to him and his family."
Despite his insistence on the hit's cleanliness, Allen may still incur a fine from the NFL. The hit, although not to the head, was high on Louis and did result in an injury.